1. Field of the Invention
The present invention relates to a wastewater treatment process, and in particular, to an automatically controlled wastewater treatment process.
2. Description of Related Art
Current wastewater treatment batch processes use a time activated system that introduces influent wastewater into a containment device and then treats the wastewater under various conditions. The treatment phase is often referred to as the reaction phase where aerobic, anoxic, and/or anaerobic conditions are used to treat influent wastewater. Under aerobic conditions, dissolved oxygen is introduced into the containment device and mixed with the influent wastewater and various microorganisms. The aerobic conditions convert ammonium and organic nitrogen found in the wastewater to nitrate. This is commonly referred to as nitrification. As used herein, ammonium (NH4) is used to describe ammonia (NH3), ammonia as nitrogen (NH3—N), and ammonium as nitrogen (NH4—N). Some treatment processes also use anoxic conditions to convert the nitrate to nitrogen gas, which is referred to as denitrification. Denitrification of the wastewater is achieved by mixing nitrate and microorganisms in the absence of dissolved oxygen.
Further, when phosphorous is present in the wastewater, the phosphorous is removed using anaerobic conditions followed by subsequent aerobic conditions. During an anaerobic process, wastewater and microorganisms are mixed together in the absence of both dissolved and chemically bound oxygen. Phosphorus is released by the microorganisms under anaerobic conditions and subsequently taken back up by the microorganisms in excess of what the microorganisms would normally take up without being introduced to anaerobic conditions.
The reaction phase is controlled by a logic program that uses periods of time inputted by an operator to promote the aerobic, anoxic, and anaerobic conditions. For example, in order to control the aerobic conditions during the reaction phase, the speed setpoint of an aeration system is controlled based on readings from dissolved oxygen (DO) instruments and an operator inputted DO setpoint.
As can be seen from the steps described above, one drawback to the current treatment processes is the need to manually input information in the system. The process of manually inputting information into a control unit to determine and adjust the DO setpoint and the amount of aerobic, anoxic, and anaerobic time required for each treatment cycle is inefficient and burdensome. A need therefore exists for a system that can automatically adjust the parameters of a wastewater treatment process in order to optimize the effluent water quality of each treatment cycle and to minimize the energy used through the entire treatment process.